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                    5.4：变换（Transform）
            
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                    5.5：Container容器
            
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                    5.6：Scaffold、TabBar、底部导航
            
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                    5.7：剪裁（Clip）
            
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                    第六章：可滚动组件
            
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                    6.1：可滚动组件简介
            
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                    6.3：ListView
            
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                    6.5：CustomScrollView
            
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                    6.6：滚动监听及控制（ScrollController）
            
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                    第七章：功能型组件
            
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                    7.2：数据共享（InheritedWidget）
            
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                    7.3： 跨组件状态共享（Provider）
            
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                    7.4：颜色和主题（Theme）
            
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                    7.5：异步UI更新（FutureBuilder、StreamBuilder）
            
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                    7.6：对话框详解
            
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                    第八章：事件处理与通知
            
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                    8.1：原始指针事件处理
            
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                    8.2：手势识别
            
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                    8.3：全局事件总线
            
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                    8.4：通知(Notification)
            
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                    第九章：动画
            
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                    9.1：Flutter动画简介
            
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                    9.2：动画结构
            
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                    9.3：自定义路由过渡动画
            
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                    9.4：Hero动画
            
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                <a href="../chapter9/stagger_animation.html">
            
                    
                    9.5：交织动画
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.2.6" data-path="../chapter9/animated_switcher.html">
            
                <a href="../chapter9/animated_switcher.html">
            
                    
                    9.6：通用“动画切换”组件（AnimatedSwitcher）
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.2.7" data-path="../chapter9/animated_widgets.html">
            
                <a href="../chapter9/animated_widgets.html">
            
                    
                    9.7：动画过渡组件
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.3" data-path="../chapter10/">
            
                <a href="../chapter10/">
            
                    
                    第十章：自定义组件
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.3.1" data-path="../chapter10/intro.html">
            
                <a href="../chapter10/intro.html">
            
                    
                    10.1：自定义组件方法简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.2" data-path="../chapter10/combine.html">
            
                <a href="../chapter10/combine.html">
            
                    
                    10.2：组合现有组件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.3" data-path="../chapter10/turn_box.html">
            
                <a href="../chapter10/turn_box.html">
            
                    
                    10.3：组合实例：TurnBox
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.4" data-path="../chapter10/custom_paint.html">
            
                <a href="../chapter10/custom_paint.html">
            
                    
                    10.4：自绘组件（CustomPaint与Canvas）
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.3.5" data-path="../chapter10/gradient_circular_progress_demo.html">
            
                <a href="../chapter10/gradient_circular_progress_demo.html">
            
                    
                    10.5：自绘实例：圆形渐变进度条(自绘)
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.4" data-path="../chapter11/">
            
                <a href="../chapter11/">
            
                    
                    第十一章：文件操作与网络请求
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.4.1" data-path="../chapter11/file_operation.html">
            
                <a href="../chapter11/file_operation.html">
            
                    
                    11.1：文件操作
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.2" data-path="../chapter11/http.html">
            
                <a href="../chapter11/http.html">
            
                    
                    11.2：Http请求-HttpClient
            
                </a>
            

            
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        <li class="chapter " data-level="3.4.3" data-path="../chapter11/dio.html">
            
                <a href="../chapter11/dio.html">
            
                    
                    11.3：Http请求-Dio package
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.4" data-path="../chapter11/download_with_chunks.html">
            
                <a href="../chapter11/download_with_chunks.html">
            
                    
                    11.4：实例：Http分块下载
            
                </a>
            

            
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        <li class="chapter " data-level="3.4.5" data-path="../chapter11/websocket.html">
            
                <a href="../chapter11/websocket.html">
            
                    
                    11.5：WebSocket
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.6" data-path="../chapter11/socket.html">
            
                <a href="../chapter11/socket.html">
            
                    
                    11.6：使用Socket API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.4.7" data-path="../chapter11/json_model.html">
            
                <a href="../chapter11/json_model.html">
            
                    
                    11.7：Json转Dart Model类
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.5" data-path="../chapter12/">
            
                <a href="../chapter12/">
            
                    
                    第十二章：包与插件
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.5.1" data-path="../chapter12/develop_package.html">
            
                <a href="../chapter12/develop_package.html">
            
                    
                    12.1：开发package
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.2" data-path="../chapter12/platform-channel.html">
            
                <a href="../chapter12/platform-channel.html">
            
                    
                    12.2：平台通道简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.3" data-path="../chapter12/develop_plugin.html">
            
                <a href="../chapter12/develop_plugin.html">
            
                    
                    12.3：开发Flutter插件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.4" data-path="../chapter12/android_implement.html">
            
                <a href="../chapter12/android_implement.html">
            
                    
                    12.4：插件开发：实现Android端API
            
                </a>
            

            
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        <li class="chapter " data-level="3.5.5" data-path="../chapter12/ios_implement.html">
            
                <a href="../chapter12/ios_implement.html">
            
                    
                    12.5：插件开发：实现IOS端API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.5.6" data-path="../chapter12/texture_platformview.html">
            
                <a href="../chapter12/texture_platformview.html">
            
                    
                    12.6：Texture和PlatformView
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.6" data-path="../chapter13/">
            
                <a href="../chapter13/">
            
                    
                    第十三章：国际化
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.6.1" data-path="../chapter13/multi_languages_support.html">
            
                <a href="../chapter13/multi_languages_support.html">
            
                    
                    13.1：让App支持多语言
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.2" data-path="../chapter13/locallization_implement.html">
            
                <a href="../chapter13/locallization_implement.html">
            
                    
                    13.2：实现Localizations
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.3" data-path="../chapter13/intl.html">
            
                <a href="../chapter13/intl.html">
            
                    
                    13.3：使用Intl包
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.6.4" data-path="../chapter13/faq.html">
            
                <a href="../chapter13/faq.html">
            
                    
                    13.4：国际化常见问题
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="3.7" data-path="../chapter14/">
            
                <a href="../chapter14/">
            
                    
                    第十四章：Flutter核心原理
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="3.7.1" data-path="../chapter14/flutter_ui_system.html">
            
                <a href="../chapter14/flutter_ui_system.html">
            
                    
                    14.1：Flutter UI系统
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.2" data-path="../chapter14/element_buildcontext.html">
            
                <a href="../chapter14/element_buildcontext.html">
            
                    
                    14.2：Element和BuildContext
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.3" data-path="../chapter14/render_object.html">
            
                <a href="../chapter14/render_object.html">
            
                    
                    14.3：RenderObject与RenderBox
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="3.7.4" data-path="../chapter14/flutter_app_startup.html">
            
                <a href="../chapter14/flutter_app_startup.html">
            
                    
                    14.4：Flutter从启动到显示
            
                </a>
            

            
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        <li class="chapter " data-level="3.7.5" data-path="../chapter14/image_and_cache.html">
            
                <a href="../chapter14/image_and_cache.html">
            
                    
                    14.5：Flutter图片加载与缓存
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

    
        
        <li class="header">实例篇</li>
        
        
    
        <li class="chapter " data-level="4.1" data-path="../chapter15/intro.html">
            
                <a href="../chapter15/intro.html">
            
                    
                    第十五章：一个完整的Flutter应用
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="4.1.1" data-path="../chapter15/intro.html">
            
                <a href="../chapter15/intro.html">
            
                    
                    15.1：应用简介
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.2" data-path="../chapter15/code_structure.html">
            
                <a href="../chapter15/code_structure.html">
            
                    
                    15.2：APP代码结构
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.3" data-path="../chapter15/models.html">
            
                <a href="../chapter15/models.html">
            
                    
                    15.3：Model类定义
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.4" data-path="../chapter15/globals.html">
            
                <a href="../chapter15/globals.html">
            
                    
                    15.4：全局变量及共享状态
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.5" data-path="../chapter15/network.html">
            
                <a href="../chapter15/network.html">
            
                    
                    15.5：网络请求封装
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.6" data-path="../chapter15/entry.html">
            
                <a href="../chapter15/entry.html">
            
                    
                    15.6：App入口及首页
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="4.1.7" data-path="../chapter15/login_page.html">
            
                <a href="../chapter15/login_page.html">
            
                    
                    15.7：登录页
            
                </a>
            

            
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        <li class="chapter " data-level="4.1.8" data-path="../chapter15/language_and_theme_setting.html">
            
                <a href="../chapter15/language_and_theme_setting.html">
            
                    
                    15.8：多语言和多主题
            
                </a>
            

            
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                                <h1 id="84-notification">8.4 Notification</h1>
<p>&#x901A;&#x77E5;&#xFF08;Notification&#xFF09;&#x662F;Flutter&#x4E2D;&#x4E00;&#x4E2A;&#x91CD;&#x8981;&#x7684;&#x673A;&#x5236;&#xFF0C;&#x5728;widget&#x6811;&#x4E2D;&#xFF0C;&#x6BCF;&#x4E00;&#x4E2A;&#x8282;&#x70B9;&#x90FD;&#x53EF;&#x4EE5;&#x5206;&#x53D1;&#x901A;&#x77E5;&#xFF0C;&#x901A;&#x77E5;&#x4F1A;&#x6CBF;&#x7740;&#x5F53;&#x524D;&#x8282;&#x70B9;&#x5411;&#x4E0A;&#x4F20;&#x9012;&#xFF0C;&#x6240;&#x6709;&#x7236;&#x8282;&#x70B9;&#x90FD;&#x53EF;&#x4EE5;&#x901A;&#x8FC7;<code>NotificationListener</code>&#x6765;&#x76D1;&#x542C;&#x901A;&#x77E5;&#x3002;Flutter&#x4E2D;&#x5C06;&#x8FD9;&#x79CD;&#x7531;&#x5B50;&#x5411;&#x7236;&#x7684;&#x4F20;&#x9012;&#x901A;&#x77E5;&#x7684;&#x673A;&#x5236;&#x79F0;&#x4E3A;<strong>&#x901A;&#x77E5;&#x5192;&#x6CE1;</strong>&#xFF08;Notification Bubbling&#xFF09;&#x3002;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x548C;&#x7528;&#x6237;&#x89E6;&#x6478;&#x4E8B;&#x4EF6;&#x5192;&#x6CE1;&#x662F;&#x76F8;&#x4F3C;&#x7684;&#xFF0C;&#x4F46;&#x6709;&#x4E00;&#x70B9;&#x4E0D;&#x540C;&#xFF1A;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x53EF;&#x4EE5;&#x4E2D;&#x6B62;&#xFF0C;&#x4F46;&#x7528;&#x6237;&#x89E6;&#x6478;&#x4E8B;&#x4EF6;&#x4E0D;&#x884C;&#x3002;</p>
<blockquote>
<p>&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x548C;Web&#x5F00;&#x53D1;&#x4E2D;&#x6D4F;&#x89C8;&#x5668;&#x4E8B;&#x4EF6;&#x5192;&#x6CE1;&#x539F;&#x7406;&#x662F;&#x76F8;&#x4F3C;&#x7684;&#xFF0C;&#x90FD;&#x662F;&#x4E8B;&#x4EF6;&#x4ECE;&#x51FA;&#x53D1;&#x6E90;&#x9010;&#x5C42;&#x5411;&#x4E0A;&#x4F20;&#x9012;&#xFF0C;&#x6211;&#x4EEC;&#x53EF;&#x4EE5;&#x5728;&#x4E0A;&#x5C42;&#x8282;&#x70B9;&#x4EFB;&#x610F;&#x4F4D;&#x7F6E;&#x6765;&#x76D1;&#x542C;&#x901A;&#x77E5;/&#x4E8B;&#x4EF6;&#xFF0C;&#x4E5F;&#x53EF;&#x4EE5;&#x7EC8;&#x6B62;&#x5192;&#x6CE1;&#x8FC7;&#x7A0B;&#xFF0C;&#x7EC8;&#x6B62;&#x5192;&#x6CE1;&#x540E;&#xFF0C;&#x901A;&#x77E5;&#x5C06;&#x4E0D;&#x4F1A;&#x518D;&#x5411;&#x4E0A;&#x4F20;&#x9012;&#x3002;</p>
</blockquote>
<p>Flutter&#x4E2D;&#x5F88;&#x591A;&#x5730;&#x65B9;&#x4F7F;&#x7528;&#x4E86;&#x901A;&#x77E5;&#xFF0C;&#x5982;&#x53EF;&#x6EDA;&#x52A8;&#x7EC4;&#x4EF6;&#xFF08;Scrollable Widget&#xFF09;&#x6ED1;&#x52A8;&#x65F6;&#x5C31;&#x4F1A;&#x5206;&#x53D1;<strong>&#x6EDA;&#x52A8;&#x901A;&#x77E5;</strong>&#xFF08;ScrollNotification&#xFF09;&#xFF0C;&#x800C;Scrollbar&#x6B63;&#x662F;&#x901A;&#x8FC7;&#x76D1;&#x542C;ScrollNotification&#x6765;&#x786E;&#x5B9A;&#x6EDA;&#x52A8;&#x6761;&#x4F4D;&#x7F6E;&#x7684;&#x3002;</p>
<p>&#x4E0B;&#x9762;&#x662F;&#x4E00;&#x4E2A;&#x76D1;&#x542C;&#x53EF;&#x6EDA;&#x52A8;&#x7EC4;&#x4EF6;&#x6EDA;&#x52A8;&#x901A;&#x77E5;&#x7684;&#x4F8B;&#x5B50;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token function">NotificationListener</span><span class="token punctuation">(</span>
  onNotification<span class="token punctuation">:</span> <span class="token punctuation">(</span>notification<span class="token punctuation">)</span><span class="token punctuation">{</span>
    <span class="token keyword">switch</span> <span class="token punctuation">(</span>notification<span class="token punctuation">.</span>runtimeType<span class="token punctuation">)</span><span class="token punctuation">{</span>
      <span class="token keyword">case</span> ScrollStartNotification<span class="token punctuation">:</span> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">&quot;&#x5F00;&#x59CB;&#x6EDA;&#x52A8;&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">break</span><span class="token punctuation">;</span>
      <span class="token keyword">case</span> ScrollUpdateNotification<span class="token punctuation">:</span> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">&quot;&#x6B63;&#x5728;&#x6EDA;&#x52A8;&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">break</span><span class="token punctuation">;</span>
      <span class="token keyword">case</span> ScrollEndNotification<span class="token punctuation">:</span> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">&quot;&#x6EDA;&#x52A8;&#x505C;&#x6B62;&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">break</span><span class="token punctuation">;</span>
      <span class="token keyword">case</span> OverscrollNotification<span class="token punctuation">:</span> <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">&quot;&#x6EDA;&#x52A8;&#x5230;&#x8FB9;&#x754C;&quot;</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">break</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span><span class="token punctuation">,</span>
  child<span class="token punctuation">:</span> ListView<span class="token punctuation">.</span><span class="token function">builder</span><span class="token punctuation">(</span>
      itemCount<span class="token punctuation">:</span> <span class="token number">100</span><span class="token punctuation">,</span>
      itemBuilder<span class="token punctuation">:</span> <span class="token punctuation">(</span>context<span class="token punctuation">,</span> index<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token function">ListTile</span><span class="token punctuation">(</span>title<span class="token punctuation">:</span> <span class="token function">Text</span><span class="token punctuation">(</span><span class="token string">&quot;$index&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span>
  <span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<p>&#x4E0A;&#x4F8B;&#x4E2D;&#x7684;&#x6EDA;&#x52A8;&#x901A;&#x77E5;&#x5982;<code>ScrollStartNotification</code>&#x3001;<code>ScrollUpdateNotification</code>&#x7B49;&#x90FD;&#x662F;&#x7EE7;&#x627F;&#x81EA;<code>ScrollNotification</code>&#x7C7B;&#xFF0C;&#x4E0D;&#x540C;&#x7C7B;&#x578B;&#x7684;&#x901A;&#x77E5;&#x5B50;&#x7C7B;&#x4F1A;&#x5305;&#x542B;&#x4E0D;&#x540C;&#x7684;&#x4FE1;&#x606F;&#xFF0C;&#x6BD4;&#x5982;<code>ScrollUpdateNotification</code>&#x6709;&#x4E00;&#x4E2A;<code>scrollDelta</code>&#x5C5E;&#x6027;&#xFF0C;&#x5B83;&#x8BB0;&#x5F55;&#x4E86;&#x79FB;&#x52A8;&#x7684;&#x4F4D;&#x79FB;&#xFF0C;&#x5176;&#x5B83;&#x901A;&#x77E5;&#x5C5E;&#x6027;&#x8BFB;&#x8005;&#x53EF;&#x4EE5;&#x81EA;&#x5DF1;&#x67E5;&#x770B;SDK&#x6587;&#x6863;&#x3002;</p>
<p>&#x4E0A;&#x4F8B;&#x4E2D;&#xFF0C;&#x6211;&#x4EEC;&#x901A;&#x8FC7;<code>NotificationListener</code>&#x6765;&#x76D1;&#x542C;&#x5B50;<code>ListView</code>&#x7684;&#x6EDA;&#x52A8;&#x901A;&#x77E5;&#x7684;&#xFF0C;<code>NotificationListener</code>&#x5B9A;&#x4E49;&#x5982;&#x4E0B;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">NotificationListener</span><span class="token operator">&lt;</span>T <span class="token keyword">extends</span> <span class="token class-name">Notification</span><span class="token operator">&gt;</span> <span class="token keyword">extends</span> <span class="token class-name">StatelessWidget</span> <span class="token punctuation">{</span>
  <span class="token keyword">const</span> <span class="token function">NotificationListener</span><span class="token punctuation">(</span><span class="token punctuation">{</span>
    Key key<span class="token punctuation">,</span>
    <span class="token metadata symbol">@required</span> <span class="token keyword">this</span><span class="token punctuation">.</span>child<span class="token punctuation">,</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>onNotification<span class="token punctuation">,</span>
  <span class="token punctuation">}</span><span class="token punctuation">)</span> <span class="token punctuation">:</span> <span class="token keyword">super</span><span class="token punctuation">(</span>key<span class="token punctuation">:</span> key<span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token comment">//&#x7701;&#x7565;&#x65E0;&#x5173;&#x4EE3;&#x7801; </span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x6211;&#x4EEC;&#x53EF;&#x4EE5;&#x770B;&#x5230;&#xFF1A;</p>
<ol>
<li><p><code>NotificationListener</code> &#x7EE7;&#x627F;&#x81EA;<code>StatelessWidget</code>&#x7C7B;&#xFF0C;&#x6240;&#x4EE5;&#x5B83;&#x53EF;&#x4EE5;&#x76F4;&#x63A5;&#x5D4C;&#x5957;&#x5230;Widget&#x6811;&#x4E2D;&#x3002;</p>
</li>
<li><p><code>NotificationListener</code> &#x53EF;&#x4EE5;&#x6307;&#x5B9A;&#x4E00;&#x4E2A;&#x6A21;&#x677F;&#x53C2;&#x6570;&#xFF0C;&#x8BE5;&#x6A21;&#x677F;&#x53C2;&#x6570;&#x7C7B;&#x578B;&#x5FC5;&#x987B;&#x662F;&#x7EE7;&#x627F;&#x81EA;<code>Notification</code>&#xFF1B;&#x5F53;&#x663E;&#x5F0F;&#x6307;&#x5B9A;&#x6A21;&#x677F;&#x53C2;&#x6570;&#x65F6;&#xFF0C;<code>NotificationListener</code> &#x4FBF;&#x53EA;&#x4F1A;&#x63A5;&#x6536;&#x8BE5;&#x53C2;&#x6570;&#x7C7B;&#x578B;&#x7684;&#x901A;&#x77E5;&#x3002;&#x4E3E;&#x4E2A;&#x4F8B;&#x5B50;&#xFF0C;&#x5982;&#x679C;&#x6211;&#x4EEC;&#x5C06;&#x4E0A;&#x4F8B;&#x5B50;&#x4EE3;&#x7801;&#x6539;&#x4E3A;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token comment">//&#x6307;&#x5B9A;&#x76D1;&#x542C;&#x901A;&#x77E5;&#x7684;&#x7C7B;&#x578B;&#x4E3A;&#x6EDA;&#x52A8;&#x7ED3;&#x675F;&#x901A;&#x77E5;(ScrollEndNotification)</span>
NotificationListener<span class="token operator">&lt;</span>ScrollEndNotification<span class="token operator">&gt;</span><span class="token punctuation">(</span>
  onNotification<span class="token punctuation">:</span> <span class="token punctuation">(</span>notification<span class="token punctuation">)</span><span class="token punctuation">{</span>
    <span class="token comment">//&#x53EA;&#x4F1A;&#x5728;&#x6EDA;&#x52A8;&#x7ED3;&#x675F;&#x65F6;&#x624D;&#x4F1A;&#x89E6;&#x53D1;&#x6B64;&#x56DE;&#x8C03;</span>
    <span class="token function">print</span><span class="token punctuation">(</span>notification<span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span><span class="token punctuation">,</span>
  child<span class="token punctuation">:</span> ListView<span class="token punctuation">.</span><span class="token function">builder</span><span class="token punctuation">(</span>
      itemCount<span class="token punctuation">:</span> <span class="token number">100</span><span class="token punctuation">,</span>
      itemBuilder<span class="token punctuation">:</span> <span class="token punctuation">(</span>context<span class="token punctuation">,</span> index<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token function">ListTile</span><span class="token punctuation">(</span>title<span class="token punctuation">:</span> <span class="token function">Text</span><span class="token punctuation">(</span><span class="token string">&quot;$index&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span>
  <span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x8FD0;&#x884C;&#x540E;&#x4FBF;&#x53EA;&#x4F1A;&#x5728;&#x6EDA;&#x52A8;&#x7ED3;&#x675F;&#x65F6;&#x5728;&#x63A7;&#x5236;&#x53F0;&#x6253;&#x5370;&#x51FA;&#x901A;&#x77E5;&#x7684;&#x4FE1;&#x606F;&#x3002;</p>
</li>
<li><p><code>onNotification</code>&#x56DE;&#x8C03;&#x4E3A;&#x901A;&#x77E5;&#x5904;&#x7406;&#x56DE;&#x8C03;&#xFF0C;&#x5176;&#x51FD;&#x6570;&#x7B7E;&#x540D;&#x5982;&#x4E0B;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">typedef</span> NotificationListenerCallback<span class="token operator">&lt;</span>T <span class="token keyword">extends</span> <span class="token class-name">Notification</span><span class="token operator">&gt;</span> <span class="token operator">=</span> bool <span class="token function">Function</span><span class="token punctuation">(</span>T notification<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<p>&#x5B83;&#x7684;&#x8FD4;&#x56DE;&#x503C;&#x7C7B;&#x578B;&#x4E3A;&#x5E03;&#x5C14;&#x503C;&#xFF0C;&#x5F53;&#x8FD4;&#x56DE;&#x503C;&#x4E3A;<code>true</code>&#x65F6;&#xFF0C;&#x963B;&#x6B62;&#x5192;&#x6CE1;&#xFF0C;&#x5176;&#x7236;&#x7EA7;Widget&#x5C06;&#x518D;&#x4E5F;&#x6536;&#x4E0D;&#x5230;&#x8BE5;&#x901A;&#x77E5;&#xFF1B;&#x5F53;&#x8FD4;&#x56DE;&#x503C;&#x4E3A;<code>false</code> &#x65F6;&#x7EE7;&#x7EED;&#x5411;&#x4E0A;&#x5192;&#x6CE1;&#x901A;&#x77E5;&#x3002;</p>
</li>
</ol>
<p>Flutter&#x7684;UI&#x6846;&#x67B6;&#x5B9E;&#x73B0;&#x4E2D;&#xFF0C;&#x9664;&#x4E86;&#x5728;&#x53EF;&#x6EDA;&#x52A8;&#x7EC4;&#x4EF6;&#x5728;&#x6EDA;&#x52A8;&#x8FC7;&#x7A0B;&#x4E2D;&#x4F1A;&#x53D1;&#x51FA;<code>ScrollNotification</code>&#x4E4B;&#x5916;&#xFF0C;&#x8FD8;&#x6709;&#x4E00;&#x4E9B;&#x5176;&#x5B83;&#x7684;&#x901A;&#x77E5;&#xFF0C;&#x5982;<code>SizeChangedLayoutNotification</code>&#x3001;<code>KeepAliveNotification</code> &#x3001;<code>LayoutChangedNotification</code>&#x7B49;&#xFF0C;Flutter&#x6B63;&#x662F;&#x901A;&#x8FC7;&#x8FD9;&#x79CD;&#x901A;&#x77E5;&#x673A;&#x5236;&#x6765;&#x4F7F;&#x7236;&#x5143;&#x7D20;&#x53EF;&#x4EE5;&#x5728;&#x4E00;&#x4E9B;&#x7279;&#x5B9A;&#x65F6;&#x673A;&#x6765;&#x505A;&#x4E00;&#x4E9B;&#x4E8B;&#x60C5;&#x3002;</p>
<h4 id="&#x81EA;&#x5B9A;&#x4E49;&#x901A;&#x77E5;">&#x81EA;&#x5B9A;&#x4E49;&#x901A;&#x77E5;</h4>
<p>&#x9664;&#x4E86;Flutter&#x5185;&#x90E8;&#x901A;&#x77E5;&#xFF0C;&#x6211;&#x4EEC;&#x4E5F;&#x53EF;&#x4EE5;&#x81EA;&#x5B9A;&#x4E49;&#x901A;&#x77E5;&#xFF0C;&#x4E0B;&#x9762;&#x6211;&#x4EEC;&#x770B;&#x770B;&#x5982;&#x4F55;&#x5B9E;&#x73B0;&#x81EA;&#x5B9A;&#x4E49;&#x901A;&#x77E5;&#xFF1A;</p>
<ol>
<li><p>&#x5B9A;&#x4E49;&#x4E00;&#x4E2A;&#x901A;&#x77E5;&#x7C7B;&#xFF0C;&#x8981;&#x7EE7;&#x627F;&#x81EA;Notification&#x7C7B;&#xFF1B;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">MyNotification</span> <span class="token keyword">extends</span> <span class="token class-name">Notification</span> <span class="token punctuation">{</span>
  <span class="token function">MyNotification</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token keyword">final</span> String msg<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</code></pre>
</li>
<li><p>&#x5206;&#x53D1;&#x901A;&#x77E5;&#x3002;</p>
<p><code>Notification</code>&#x6709;&#x4E00;&#x4E2A;<code>dispatch(context)</code>&#x65B9;&#x6CD5;&#xFF0C;&#x5B83;&#x662F;&#x7528;&#x4E8E;&#x5206;&#x53D1;&#x901A;&#x77E5;&#x7684;&#xFF0C;&#x6211;&#x4EEC;&#x8BF4;&#x8FC7;<code>context</code>&#x5B9E;&#x9645;&#x4E0A;&#x5C31;&#x662F;&#x64CD;&#x4F5C;<code>Element</code>&#x7684;&#x4E00;&#x4E2A;&#x63A5;&#x53E3;&#xFF0C;&#x5B83;&#x4E0E;<code>Element</code>&#x6811;&#x4E0A;&#x7684;&#x8282;&#x70B9;&#x662F;&#x5BF9;&#x5E94;&#x7684;&#xFF0C;&#x901A;&#x77E5;&#x4F1A;&#x4ECE;<code>context</code>&#x5BF9;&#x5E94;&#x7684;<code>Element</code>&#x8282;&#x70B9;&#x5411;&#x4E0A;&#x5192;&#x6CE1;&#x3002;</p>
</li>
</ol>
<p>&#x4E0B;&#x9762;&#x6211;&#x4EEC;&#x770B;&#x4E00;&#x4E2A;&#x5B8C;&#x6574;&#x7684;&#x4F8B;&#x5B50;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">NotificationRoute</span> <span class="token keyword">extends</span> <span class="token class-name">StatefulWidget</span> <span class="token punctuation">{</span>
  <span class="token metadata symbol">@override</span>
  NotificationRouteState <span class="token function">createState</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">NotificationRouteState</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">NotificationRouteState</span> <span class="token keyword">extends</span> <span class="token class-name">State</span><span class="token operator">&lt;</span>NotificationRoute<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
  String _msg<span class="token operator">=</span><span class="token string">&quot;&quot;</span><span class="token punctuation">;</span>
  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">//&#x76D1;&#x542C;&#x901A;&#x77E5;  </span>
    <span class="token keyword">return</span> NotificationListener<span class="token operator">&lt;</span>MyNotification<span class="token operator">&gt;</span><span class="token punctuation">(</span>
      onNotification<span class="token punctuation">:</span> <span class="token punctuation">(</span>notification<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
          _msg<span class="token operator">+=</span>notification<span class="token punctuation">.</span>msg<span class="token operator">+</span><span class="token string">&quot;  &quot;</span><span class="token punctuation">;</span>
        <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
       <span class="token keyword">return</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span><span class="token punctuation">,</span>
      child<span class="token punctuation">:</span> <span class="token function">Center</span><span class="token punctuation">(</span>
        child<span class="token punctuation">:</span> <span class="token function">Column</span><span class="token punctuation">(</span>
          mainAxisSize<span class="token punctuation">:</span> MainAxisSize<span class="token punctuation">.</span>min<span class="token punctuation">,</span>
          children<span class="token punctuation">:</span> <span class="token operator">&lt;</span>Widget<span class="token operator">&gt;</span><span class="token punctuation">[</span>
<span class="token comment">//          RaisedButton(</span>
<span class="token comment">//           onPressed: () =&gt; MyNotification(&quot;Hi&quot;).dispatch(context),</span>
<span class="token comment">//           child: Text(&quot;Send Notification&quot;),</span>
<span class="token comment">//          ),  </span>
            <span class="token function">Builder</span><span class="token punctuation">(</span>
              builder<span class="token punctuation">:</span> <span class="token punctuation">(</span>context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
                <span class="token keyword">return</span> <span class="token function">RaisedButton</span><span class="token punctuation">(</span>
                  <span class="token comment">//&#x6309;&#x94AE;&#x70B9;&#x51FB;&#x65F6;&#x5206;&#x53D1;&#x901A;&#x77E5;  </span>
                  onPressed<span class="token punctuation">:</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">=</span><span class="token operator">&gt;</span> <span class="token function">MyNotification</span><span class="token punctuation">(</span><span class="token string">&quot;Hi&quot;</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">dispatch</span><span class="token punctuation">(</span>context<span class="token punctuation">)</span><span class="token punctuation">,</span>
                  child<span class="token punctuation">:</span> <span class="token function">Text</span><span class="token punctuation">(</span><span class="token string">&quot;Send Notification&quot;</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
                <span class="token punctuation">)</span><span class="token punctuation">;</span>
              <span class="token punctuation">}</span><span class="token punctuation">,</span>
            <span class="token punctuation">)</span><span class="token punctuation">,</span>
            <span class="token function">Text</span><span class="token punctuation">(</span>_msg<span class="token punctuation">)</span>
          <span class="token punctuation">]</span><span class="token punctuation">,</span>
        <span class="token punctuation">)</span><span class="token punctuation">,</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>

<span class="token keyword">class</span> <span class="token class-name">MyNotification</span> <span class="token keyword">extends</span> <span class="token class-name">Notification</span> <span class="token punctuation">{</span>
  <span class="token function">MyNotification</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token keyword">final</span> String msg<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E2D;&#xFF0C;&#x6211;&#x4EEC;&#x6BCF;&#x70B9;&#x4E00;&#x6B21;&#x6309;&#x94AE;&#x5C31;&#x4F1A;&#x5206;&#x53D1;&#x4E00;&#x4E2A;<code>MyNotification</code>&#x7C7B;&#x578B;&#x7684;&#x901A;&#x77E5;&#xFF0C;&#x6211;&#x4EEC;&#x5728;Widget&#x6839;&#x4E0A;&#x76D1;&#x542C;&#x901A;&#x77E5;&#xFF0C;&#x6536;&#x5230;&#x901A;&#x77E5;&#x540E;&#x6211;&#x4EEC;&#x5C06;&#x901A;&#x77E5;&#x901A;&#x8FC7;Text&#x663E;&#x793A;&#x5728;&#x5C4F;&#x5E55;&#x4E0A;&#x3002;</p>
<blockquote>
<p>&#x6CE8;&#x610F;&#xFF1A;&#x4EE3;&#x7801;&#x4E2D;&#x6CE8;&#x91CA;&#x7684;&#x90E8;&#x5206;&#x662F;&#x4E0D;&#x80FD;&#x6B63;&#x5E38;&#x5DE5;&#x4F5C;&#x7684;&#xFF0C;&#x56E0;&#x4E3A;&#x8FD9;&#x4E2A;<code>context</code>&#x662F;&#x6839;Context&#xFF0C;&#x800C;NotificationListener&#x662F;&#x76D1;&#x542C;&#x7684;&#x5B50;&#x6811;&#xFF0C;&#x6240;&#x4EE5;&#x6211;&#x4EEC;&#x901A;&#x8FC7;<code>Builder</code>&#x6765;&#x6784;&#x5EFA;RaisedButton&#xFF0C;&#x6765;&#x83B7;&#x5F97;&#x6309;&#x94AE;&#x4F4D;&#x7F6E;&#x7684;context&#x3002;</p>
</blockquote>
<p>&#x8FD0;&#x884C;&#x6548;&#x679C;&#x5982;&#x56FE;8-6&#x6240;&#x793A;&#xFF1A;</p>
<p><img src="https://pcdn.flutterchina.club/imgs/8-6.png" alt="&#x56FE;8-6"></p>
<h3 id="&#x963B;&#x6B62;&#x5192;&#x6CE1;">&#x963B;&#x6B62;&#x5192;&#x6CE1;</h3>
<p>&#x6211;&#x4EEC;&#x5C06;&#x4E0A;&#x9762;&#x7684;&#x4F8B;&#x5B50;&#x6539;&#x4E3A;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">class</span> <span class="token class-name">NotificationRouteState</span> <span class="token keyword">extends</span> <span class="token class-name">State</span><span class="token operator">&lt;</span>NotificationRoute<span class="token operator">&gt;</span> <span class="token punctuation">{</span>
  String _msg<span class="token operator">=</span><span class="token string">&quot;&quot;</span><span class="token punctuation">;</span>
  <span class="token metadata symbol">@override</span>
  Widget <span class="token function">build</span><span class="token punctuation">(</span>BuildContext context<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">//&#x76D1;&#x542C;&#x901A;&#x77E5;</span>
    <span class="token keyword">return</span> NotificationListener<span class="token operator">&lt;</span>MyNotification<span class="token operator">&gt;</span><span class="token punctuation">(</span>
      onNotification<span class="token punctuation">:</span> <span class="token punctuation">(</span>notification<span class="token punctuation">)</span><span class="token punctuation">{</span>
        <span class="token function">print</span><span class="token punctuation">(</span>notification<span class="token punctuation">.</span>msg<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">//&#x6253;&#x5370;&#x901A;&#x77E5;</span>
        <span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
      <span class="token punctuation">}</span><span class="token punctuation">,</span>
      child<span class="token punctuation">:</span> NotificationListener<span class="token operator">&lt;</span>MyNotification<span class="token operator">&gt;</span><span class="token punctuation">(</span>
        onNotification<span class="token punctuation">:</span> <span class="token punctuation">(</span>notification<span class="token punctuation">)</span> <span class="token punctuation">{</span>
          <span class="token function">setState</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
            _msg<span class="token operator">+=</span>notification<span class="token punctuation">.</span>msg<span class="token operator">+</span><span class="token string">&quot;  &quot;</span><span class="token punctuation">;</span>
          <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
          <span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;</span> 
        <span class="token punctuation">}</span><span class="token punctuation">,</span>
        child<span class="token punctuation">:</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token comment">//&#x7701;&#x7565;&#x91CD;&#x590D;&#x4EE3;&#x7801;</span>
      <span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</code></pre>
<p>&#x4E0A;&#x5217;&#x4E2D;&#x4E24;&#x4E2A;<code>NotificationListener</code>&#x8FDB;&#x884C;&#x4E86;&#x5D4C;&#x5957;&#xFF0C;&#x5B50;<code>NotificationListener</code>&#x7684;<code>onNotification</code>&#x56DE;&#x8C03;&#x8FD4;&#x56DE;&#x4E86;<code>false</code>&#xFF0C;&#x8868;&#x793A;&#x4E0D;&#x963B;&#x6B62;&#x5192;&#x6CE1;&#xFF0C;&#x6240;&#x4EE5;&#x7236;<code>NotificationListener</code>&#x4ECD;&#x7136;&#x4F1A;&#x53D7;&#x5230;&#x901A;&#x77E5;&#xFF0C;&#x6240;&#x4EE5;&#x63A7;&#x5236;&#x53F0;&#x4F1A;&#x6253;&#x5370;&#x51FA;&#x901A;&#x77E5;&#x4FE1;&#x606F;&#xFF1B;&#x5982;&#x679C;&#x5C06;&#x5B50;<code>NotificationListener</code>&#x7684;<code>onNotification</code>&#x56DE;&#x8C03;&#x7684;&#x8FD4;&#x56DE;&#x503C;&#x6539;&#x4E3A;<code>true</code>&#xFF0C;&#x5219;&#x7236;<code>NotificationListener</code>&#x4FBF;&#x4E0D;&#x4F1A;&#x518D;&#x6253;&#x5370;&#x901A;&#x77E5;&#x4E86;&#xFF0C;&#x56E0;&#x4E3A;&#x5B50;<code>NotificationListener</code>&#x5DF2;&#x7ECF;&#x7EC8;&#x6B62;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x4E86;&#x3002;</p>
<h3 id="&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x539F;&#x7406;">&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x539F;&#x7406;</h3>
<p>&#x6211;&#x4EEC;&#x5728;&#x4E0A;&#x9762;&#x4ECB;&#x7ECD;&#x4E86;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x7684;&#x73B0;&#x8C61;&#x53CA;&#x4F7F;&#x7528;&#xFF0C;&#x73B0;&#x5728;&#x6211;&#x4EEC;&#x66F4;&#x6DF1;&#x5165;&#x4E00;&#x4E9B;&#xFF0C;&#x4ECB;&#x7ECD;&#x4E00;&#x4E0B;Flutter&#x6846;&#x67B6;&#x4E2D;&#x662F;&#x5982;&#x4F55;&#x5B9E;&#x73B0;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x7684;&#x3002;&#x4E3A;&#x4E86;&#x641E;&#x6E05;&#x695A;&#x8FD9;&#x4E2A;&#x95EE;&#x9898;&#xFF0C;&#x5C31;&#x5FC5;&#x987B;&#x770B;&#x4E00;&#x4E0B;&#x6E90;&#x7801;&#xFF0C;&#x6211;&#x4EEC;&#x4ECE;&#x901A;&#x77E5;&#x5206;&#x53D1;&#x7684;&#x7684;&#x6E90;&#x5934;&#x51FA;&#x53D1;&#xFF0C;&#x7136;&#x540E;&#x518D;&#x987A;&#x85E4;&#x6478;&#x74DC;&#x3002;&#x7531;&#x4E8E;&#x901A;&#x77E5;&#x662F;&#x901A;&#x8FC7;<code>Notification</code>&#x7684;<code>dispatch(context)</code>&#x65B9;&#x6CD5;&#x53D1;&#x51FA;&#x7684;&#xFF0C;&#x90A3;&#x6211;&#x4EEC;&#x5148;&#x770B;&#x770B;<code>dispatch(context)</code>&#x65B9;&#x6CD5;&#x4E2D;&#x505A;&#x4E86;&#x4EC0;&#x4E48;&#xFF0C;&#x4E0B;&#x9762;&#x662F;&#x76F8;&#x5173;&#x6E90;&#x7801;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token keyword">void</span> <span class="token function">dispatch</span><span class="token punctuation">(</span>BuildContext target<span class="token punctuation">)</span> <span class="token punctuation">{</span>
  target<span class="token operator">?</span><span class="token punctuation">.</span><span class="token function">visitAncestorElements</span><span class="token punctuation">(</span>visitAncestor<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</code></pre>
<p><code>dispatch(context)</code>&#x4E2D;&#x8C03;&#x7528;&#x4E86;&#x5F53;&#x524D;context&#x7684;<code>visitAncestorElements</code>&#x65B9;&#x6CD5;&#xFF0C;&#x8BE5;&#x65B9;&#x6CD5;&#x4F1A;&#x4ECE;&#x5F53;&#x524D;Element&#x5F00;&#x59CB;&#x5411;&#x4E0A;&#x904D;&#x5386;&#x7236;&#x7EA7;&#x5143;&#x7D20;&#xFF1B;<code>visitAncestorElements</code>&#x6709;&#x4E00;&#x4E2A;&#x904D;&#x5386;&#x56DE;&#x8C03;&#x53C2;&#x6570;&#xFF0C;&#x5728;&#x904D;&#x5386;&#x8FC7;&#x7A0B;&#x4E2D;&#x5BF9;&#x904D;&#x5386;&#x5230;&#x7684;&#x7236;&#x7EA7;&#x5143;&#x7D20;&#x90FD;&#x4F1A;&#x6267;&#x884C;&#x8BE5;&#x56DE;&#x8C03;&#x3002;&#x904D;&#x5386;&#x7684;&#x7EC8;&#x6B62;&#x6761;&#x4EF6;&#x662F;&#xFF1A;&#x5DF2;&#x7ECF;&#x904D;&#x5386;&#x5230;&#x6839;Element&#x6216;&#x67D0;&#x4E2A;&#x904D;&#x5386;&#x56DE;&#x8C03;&#x8FD4;&#x56DE;<code>false</code>&#x3002;&#x6E90;&#x7801;&#x4E2D;&#x4F20;&#x7ED9;<code>visitAncestorElements</code>&#x65B9;&#x6CD5;&#x7684;&#x904D;&#x5386;&#x56DE;&#x8C03;&#x4E3A;<code>visitAncestor</code>&#x65B9;&#x6CD5;&#xFF0C;&#x6211;&#x4EEC;&#x770B;&#x770B;<code>visitAncestor</code>&#x65B9;&#x6CD5;&#x7684;&#x5B9E;&#x73B0;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart"><span class="token comment">//&#x904D;&#x5386;&#x56DE;&#x8C03;&#xFF0C;&#x4F1A;&#x5BF9;&#x6BCF;&#x4E00;&#x4E2A;&#x7236;&#x7EA7;Element&#x6267;&#x884C;&#x6B64;&#x56DE;&#x8C03;</span>
bool <span class="token function">visitAncestor</span><span class="token punctuation">(</span>Element element<span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token comment">//&#x5224;&#x65AD;&#x5F53;&#x524D;element&#x5BF9;&#x5E94;&#x7684;Widget&#x662F;&#x5426;&#x662F;NotificationListener&#x3002;</span>

  <span class="token comment">//&#x7531;&#x4E8E;NotificationListener&#x662F;&#x7EE7;&#x627F;&#x81EA;StatelessWidget&#xFF0C;</span>
  <span class="token comment">//&#x6545;&#x5148;&#x5224;&#x65AD;&#x662F;&#x5426;&#x662F;StatelessElement</span>
  <span class="token keyword">if</span> <span class="token punctuation">(</span>element <span class="token operator">is</span> StatelessElement<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">//&#x662F;StatelessElement&#xFF0C;&#x5219;&#x83B7;&#x53D6;element&#x5BF9;&#x5E94;&#x7684;Widget&#xFF0C;&#x5224;&#x65AD;</span>
    <span class="token comment">//&#x662F;&#x5426;&#x662F;NotificationListener &#x3002;</span>
    <span class="token keyword">final</span> StatelessWidget widget <span class="token operator">=</span> element<span class="token punctuation">.</span>widget<span class="token punctuation">;</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>widget <span class="token operator">is</span> NotificationListener<span class="token operator">&lt;</span>Notification<span class="token operator">&gt;</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token comment">//&#x662F;NotificationListener&#xFF0C;&#x5219;&#x8C03;&#x7528;&#x8BE5;NotificationListener&#x7684;_dispatch&#x65B9;&#x6CD5;</span>
      <span class="token keyword">if</span> <span class="token punctuation">(</span>widget<span class="token punctuation">.</span><span class="token function">_dispatch</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">,</span> element<span class="token punctuation">)</span><span class="token punctuation">)</span> 
        <span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>
  <span class="token keyword">return</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
</code></pre>
<p><code>visitAncestor</code>&#x4F1A;&#x5224;&#x65AD;&#x6BCF;&#x4E00;&#x4E2A;&#x904D;&#x5386;&#x5230;&#x7684;&#x7236;&#x7EA7;Widget&#x662F;&#x5426;&#x662F;<code>NotificationListener</code>&#xFF0C;&#x5982;&#x679C;&#x4E0D;&#x662F;&#xFF0C;&#x5219;&#x8FD4;&#x56DE;<code>true</code>&#x7EE7;&#x7EED;&#x5411;&#x4E0A;&#x904D;&#x5386;&#xFF0C;&#x5982;&#x679C;&#x662F;&#xFF0C;&#x5219;&#x8C03;&#x7528;<code>NotificationListener</code>&#x7684;<code>_dispatch</code>&#x65B9;&#x6CD5;&#xFF0C;&#x6211;&#x4EEC;&#x770B;&#x770B;<code>_dispatch</code>&#x65B9;&#x6CD5;&#x7684;&#x6E90;&#x7801;&#xFF1A;</p>
<pre class="language-"><code class="lang-dart">  bool <span class="token function">_dispatch</span><span class="token punctuation">(</span>Notification notification<span class="token punctuation">,</span> Element element<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">// &#x5982;&#x679C;&#x901A;&#x77E5;&#x76D1;&#x542C;&#x5668;&#x4E0D;&#x4E3A;&#x7A7A;&#xFF0C;&#x5E76;&#x4E14;&#x5F53;&#x524D;&#x901A;&#x77E5;&#x7C7B;&#x578B;&#x662F;&#x8BE5;NotificationListener</span>
    <span class="token comment">// &#x76D1;&#x542C;&#x7684;&#x901A;&#x77E5;&#x7C7B;&#x578B;&#xFF0C;&#x5219;&#x8C03;&#x7528;&#x5F53;&#x524D;NotificationListener&#x7684;onNotification</span>
    <span class="token keyword">if</span> <span class="token punctuation">(</span>onNotification <span class="token operator">!=</span> <span class="token keyword">null</span> <span class="token operator">&amp;&amp;</span> notification <span class="token operator">is</span> T<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">final</span> bool result <span class="token operator">=</span> <span class="token function">onNotification</span><span class="token punctuation">(</span>notification<span class="token punctuation">)</span><span class="token punctuation">;</span>
      <span class="token comment">// &#x8FD4;&#x56DE;&#x503C;&#x51B3;&#x5B9A;&#x662F;&#x5426;&#x7EE7;&#x7EED;&#x5411;&#x4E0A;&#x904D;&#x5386;</span>
      <span class="token keyword">return</span> result <span class="token operator">==</span> <span class="token boolean">true</span><span class="token punctuation">;</span> 
    <span class="token punctuation">}</span>
    <span class="token keyword">return</span> <span class="token boolean">false</span><span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
</code></pre>
<p>&#x6211;&#x4EEC;&#x53EF;&#x4EE5;&#x770B;&#x5230;<code>NotificationListener</code>&#x7684;<code>onNotification</code>&#x56DE;&#x8C03;&#x6700;&#x7EC8;&#x662F;&#x5728;<code>_dispatch</code>&#x65B9;&#x6CD5;&#x4E2D;&#x6267;&#x884C;&#x7684;&#xFF0C;&#x7136;&#x540E;&#x4F1A;&#x6839;&#x636E;&#x8FD4;&#x56DE;&#x503C;&#x6765;&#x786E;&#x5B9A;&#x662F;&#x5426;&#x7EE7;&#x7EED;&#x5411;&#x4E0A;&#x5192;&#x6CE1;&#x3002;&#x4E0A;&#x9762;&#x7684;&#x6E90;&#x7801;&#x5B9E;&#x73B0;&#x5176;&#x5B9E;&#x5E76;&#x4E0D;&#x590D;&#x6742;&#xFF0C;&#x901A;&#x8FC7;&#x9605;&#x8BFB;&#x8FD9;&#x4E9B;&#x6E90;&#x7801;&#xFF0C;&#x4E00;&#x4E9B;&#x989D;&#x5916;&#x7684;&#x70B9;&#x8BFB;&#x8005;&#x53EF;&#x4EE5;&#x6CE8;&#x610F;&#x4E00;&#x4E0B;&#xFF1A;</p>
<ol>
<li><code>Context</code>&#x4E0A;&#x4E5F;&#x63D0;&#x4F9B;&#x4E86;&#x904D;&#x5386;Element&#x6811;&#x7684;&#x65B9;&#x6CD5;&#x3002;</li>
<li>&#x6211;&#x4EEC;&#x53EF;&#x4EE5;&#x901A;&#x8FC7;<code>Element.widget</code>&#x5F97;&#x5230;<code>element</code>&#x8282;&#x70B9;&#x5BF9;&#x5E94;&#x7684;widget&#xFF1B;&#x6211;&#x4EEC;&#x5DF2;&#x7ECF;&#x53CD;&#x590D;&#x8BB2;&#x8FC7;Widget&#x548C;Element&#x7684;&#x5BF9;&#x5E94;&#x5173;&#x7CFB;&#xFF0C;&#x8BFB;&#x8005;&#x901A;&#x8FC7;&#x8FD9;&#x4E9B;&#x6E90;&#x7801;&#x6765;&#x52A0;&#x6DF1;&#x7406;&#x89E3;&#x3002;</li>
</ol>
<h3 id="&#x603B;&#x7ED3;">&#x603B;&#x7ED3;</h3>
<p>Flutter&#x4E2D;&#x901A;&#x8FC7;&#x901A;&#x77E5;&#x5192;&#x6CE1;&#x5B9E;&#x73B0;&#x4E86;&#x4E00;&#x5957;&#x81EA;&#x4F4E;&#x5411;&#x4E0A;&#x7684;&#x6D88;&#x606F;&#x4F20;&#x9012;&#x673A;&#x5236;&#xFF0C;&#x8FD9;&#x4E2A;&#x548C;Web&#x5F00;&#x53D1;&#x4E2D;&#x6D4F;&#x89C8;&#x5668;&#x7684;&#x4E8B;&#x4EF6;&#x5192;&#x6CE1;&#x539F;&#x7406;&#x7C7B;&#x4F3C;&#xFF0C;Web&#x5F00;&#x53D1;&#x8005;&#x53EF;&#x4EE5;&#x7C7B;&#x6BD4;&#x5B66;&#x4E60;&#x3002;&#x53E6;&#x5916;&#x6211;&#x4EEC;&#x901A;&#x8FC7;&#x6E90;&#x7801;&#x4E86;&#x89E3;&#x4E86;Flutter &#x901A;&#x77E5;&#x5192;&#x6CE1;&#x7684;&#x6D41;&#x7A0B;&#x548C;&#x539F;&#x7406;&#xFF0C;&#x4FBF;&#x4E8E;&#x8BFB;&#x8005;&#x52A0;&#x6DF1;&#x7406;&#x89E3;&#x548C;&#x5B66;&#x4E60;Flutter&#x7684;&#x6846;&#x67B6;&#x8BBE;&#x8BA1;&#x601D;&#x60F3;&#xFF0C;&#x5728;&#x6B64;&#xFF0C;&#x518D;&#x6B21;&#x5EFA;&#x8BAE;&#x8BFB;&#x8005;&#x5728;&#x5E73;&#x65F6;&#x5B66;&#x4E60;&#x4E2D;&#x80FD;&#x591A;&#x770B;&#x770B;&#x6E90;&#x7801;&#xFF0C;&#x5B9A;&#x4F1A;&#x53D7;&#x76CA;&#x532A;&#x6D45;&#x3002;</p>

                                
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